Getting codes:
If you register the game at http://www.codemasters.com/register, they will send you two cheats. You first need to sort out code "m" at the website first.

Bonus competitions:
When you complete the LOLA World championship, you need $8 million to unlock two more competitions involving the cars you win in one-on-one challenges. The class "B" championship involves all cars from the row with the Mini Cooper S, while the class "A" championship involves the last row of cars with the Tuscan speed 12 and Toyota GT1. Make sure you have as many cars as possible as these race are tricky and you will need a balanced car.